If you don't use k8s and just run bespoke containers you still have to figure out how those containers find and talk to each other. Maybe you run some custom DNS setup, maybe you run a purpose built service discovery thing like consul, etc. And you have to figure out how you'll do networking to support public/internet-facing workloads vs. private internal services (and how each can talk to the other).
But... if you just use k8s you get things like basic service discovery, networking, ingress, etc. with it and don't have to figure out bespoke solutions (that you'll just chuck anyways once you move to k8s).
I do agree though I would be very hesitant to immediately dive in running stateful workloads like databases, etc. on my own k8s cluster. The cloud hosted database services that every provider has is such a significant time and complexity saver, especially if your databases are just getting started and small-ish.
But... if you just use k8s you get things like basic service discovery, networking, ingress, etc. with it and don't have to figure out bespoke solutions (that you'll just chuck anyways once you move to k8s).
I do agree though I would be very hesitant to immediately dive in running stateful workloads like databases, etc. on my own k8s cluster. The cloud hosted database services that every provider has is such a significant time and complexity saver, especially if your databases are just getting started and small-ish.